Projection apparatus



Sept. 20, 1938. v, PRATT 2,130,561

PROJECTION APPARATUS Filed March 11, 1936 2 Sheets-Sheet l lEtl- INVENTOR VERNEURE-WJT Sept. 20, 1938. v. E. PRATT PROJECTION APPARATUS Filed March 11, 1936 2 Sheets-Sheet 2 IINVENTOR VERNE v11 E. PRATT ATTORNEY Patented Sept. 20, 1938 PROJECTION APPARATUS Verneur E. Pratt, Stamford, Conn., assignor, by

mesne assignments, to Plant Liquidation Corporation, a corporation of New Jersey Application March 11, 1936, Serial No. 68,206

9 Claims.

This invention relates to projection apparatus. An object of the invention is toprovide a combined lens and film guide for use in projectors. Another object is to provide a combined lens and film guide which is cylindrical in shape.

A further object is to provide a combined cylindrical lens and film guide which is rotatably mounted and adapted to be freely rotated by the film in the latters contact with the lens surface whereby slippage between the film and guiding means is eliminated.

Other objects and advantages of the invention will become apparent during the course of the following description in connection with the accompanying drawings, in which Figure 1 is a side view partly in section showing the device incorporated in a projector;

Figure 2 is a front elevation of the device;

Figure 3 is a perspective view illustrating the engagement of the. film with the rotary lens and guide;

Figure 4 is a, diagrammatic view of the device operating as a condensing lens:

Figure 5 is a diagrammatic view showing the 5 operation of the retracting bail.

Referring to Figure 1, the numeral l0 generally denotes a reading or reference projector of the type described and claimed in co-pending application Serial No. 68,204, filed March 11, 1936, and having a casing H in which is secured a lamp housing l2. A lamp I3 is held in a socket 44 secured in a sleeve 45 formed on or fastened to a plate 16. The plate I6 is slidably mounted in rails 11 and 98 secured to the front and rear 35 walls of the housing l2, and is adapted to be moved therein by means of a pinion 19 meshing with a rack 20 on the underside of the plate. The pinion 20 is secured on the end of a shaft 2| journalled at 22 in the housing l2. A sec- 40 ond pinion 23 on the front end of the shaft 2! meshes with a second rack 24 secured to a yoke member 25 slidably mounted in transverse rails 26 and 21 secured to the front wall of the casing II. The yoke 25 carries a third rack 28 mesh- 45 ing with a pinion 29 on a shaft 30 journalled in the front of the casing II and having an exierior knob 3|. By turning the knob 3|, the

yoke 25 is shifted transversely in the casing l0,-

causing the second rack 24 to revolve the sec- 50 end pinion 23, shaft 2! and pinion 20, the pinion 20 moving the lamp assembly as noted.

A cylindrical lens 32, having end caps 33 and 34, as shown in Figs. 2 and 3, is freely rotatable on pivots 35 and 36 centrally engaging the end 55 caps, the pivots 35 and 36 being secured in the arms 31 and 38 of a bracket 39 fastened to the housing l2 in line with the lamp l3. The lens 32 extends into the housing I2, and a light and heat shield 40 may be disposed between the lens and lamp as shown in Fig. 1, the shield 40 hav- 5 ing a slot 4| through which the light is directed by a suitable concentrating reflector 42. It will be understood that the arrangement shown in Fig. 4 may be used, in which the shield 40 is omitted. In this arrangement, the lens 32 acts as a condensing lens to concentrate the light from the lamp l3 and a reflector 43 of larger radius of curvature than that shown in Fig. 1, is employed.

A film magazine 44 containing upper and lower film reels 45 and 46 is disposed in the casing II adjacent the lamp housing l2 and partly encircling the cylindrical lens 32 as shown in Fig. 1. A film 41, wound on the reels 45 and 46, runs over guide rollers 48 and 49 between which it engages and follows a segment of the cylindrical surface of the lens 32.

This magazine is more fully described in the co-pending application Serial Number 68,205, filed concurrently herewith. The magazine casing has a semi-circular aperture on one side, to receive a portion of the cylindrical lens 32 which consequently engages the film 41 within the magazine casing, and a pocket 56 in the opposite side wall. The wall of this pocket has a slot 58 therein to permit light to pass through the magazine and through the film.

The reels 45 and 46 are adapted to be selectively driven through their hubs by any suitable means such as manual cranks (not shown) in the rear side of the machine. Preferably either reel from which the film is being unwound is revolved through the tension of the film itself as the latter is wound on the other reel, the winding reel revolving with sufficient friction to tend to retard its rotation, by which means the film 41 may be kept taut at all times and, therefore, positively engaged with the lens 32.

A bail 50, Figures 1, 2 and 5, is journalled on the outer ends of pivots 35 and 36 so as to span the length of the lens 32 and its end caps 33 and 34. The outer end of the bail 50 is formed as an angular shoe 5| sloping toward the axis of the lens 32. The bail 50 has thereon a lever 52, shown in Figure 5. In normal position, the bail is swung upward as shown in Figures 1 and 2, to clear the film 41 and allow the latter to embrace the lens 32 without interference.

When it is desired to remove the magazine 44 and film 41 from the projector, the lever 52 is 55 thrown downward as shown in Figure 5, the ball 50 engaging the film 41 and drawing it clear of the lens 32 and end caps 33 and 34. The magazine may now be withdrawn laterally from the projector, the film riding the ball 50 and thus clearing the lens assembly.

When the magazine is replaced in the projector, the bail being in the position shown in Figure 5, the film 41 engages the sloping shoe which guides it into its position, shown in the above figure. The bail 50 is then swung upward to clear the film, after which the first rotation of either reel draws the film taut around the lens 32, as shown in Figure 1.

From the foregoing it is evident that the bail 50 with its sloping shoe 5| makes it unnecessary to touch the film with the fingers in removing or replacing the magazine in the projector, and that the projector itself contains no special guide rollers, or film troughs, the rotary lens 32 itself acting as a rolling guide in cooperation with the rollers 48 and 49 in the self-contained magazine 44 to locate the film accurately for projection.

A sleeve 53, Figure 1, formed on or secured to the yoke 25, holds a lens barrel 54 in which is disposed a small barrel 55 containing the usual projection lens combination, the small barrel 55 and its contained parts being hereinafter referred to as the projection lens.

The sleeve 53 and barrel 54 extend rearwardly into a pocket 56 in the magazine 44. The wall 51 of the pocket 56 has a transverse slot 58 in line with the projection lens 55, the middle of the lens 32 and the filament 59 of the lamp l3.

In operation, light from the lamp i3 is concentrated on a narrow transverse portion 60 of the film 41 as indicated in dotted and dashed lines in Figure 3. The concentration of light may be accomplished either as shown in Figure 1, in which the light from the filament 59 and concentrating reflector 42 is received by the lens 32 on its emergence from the slot 4| and directed through the lens in a substantially fiat beam to the film; or as shown in Figure 4, wherein the lens 32 itself condenses the light and concentrates it on the film portion 60.

The film 41, as normally used in the reference or reading projector shown, carries microscopic images of reading or reference material arranged in parallel columns disposed side by side across the width of the film as indicated at 6|, Figure 3, thus allowing a large amount of data such as that contained in a telephone directory to be concentrated in small space. When it is desired to observe a particular line of a particular column the projector lens system is shifted laterally bymeans of the knob 3| as previously described until the lens 54 comes into registry with the desired column such as Bla, Figure 3, and the film fed upward or downward by rotating its reels until the required line is brought into the illuminated area 60. In'the projector as shown in Figure 1, the light source is shifted in synchronism with the projection lens 55 as previously described, the shield 40 with slot 4I restricting the illumination at 60 to the particular column in registry with the projection lens, while in the lighting arrangementshown in Figure 4, the entire area 60 is illuminated at all times. In either case, the lens 55 projects an image,of the registered line against an angular mirror 62 in the front of the sleeve 53, from which mirror the image is refiected through an aperture 63 in the bottom of 53 and via successive angular mirrors G4, 65 and 66 to a translucent screen 61 secured in a hood 6| on the top of the casing II.

A shaft 68, journalled in the yoke 25 and carrying a worm engaging threads 1| in the top of the lens barrel 54, extends outward through a lateral slot 12 in the front of the casing II and has an exterior knob 13. By rotating the knob 13 the lens barrel 54 may be moved inward or outward, thus providing an adjustment for the projection lens by which the image on the screen 61 may be brought into proper focus. The lateral slot 12 provides clearance for the shaft 69 when the yoke 25 is traversed.

Due to the small height of the illuminated area 60 and the large diameter of the lens 32, thetotal curvature within the area projected is so small that projection takes place substantially from a plane, ensuring a sharp projection of the entire image. The bending of the film around the circumference of the lens assures that no lateral buckling can occur.

The free rotation of the lens 32 by the film 41 in rolling contact avoids abrasion and wear of the film surface such as arises in projectors wherein the film travels over stationary guides. The rotary guide being a lens throughout the entire width of the film, the entire film area is available for projection in projectors such as the type illustrated, wherein no sprockets are necessary.

While the invention has been described in preferred form, it is not limited to the precise structures illustrated, as various modifications may be made without departing from the scope of the appended claims.

What is claimed is:

1. In a projector including a movable film anda housing containing a light source, in combination, trunnions on said housing, said housing having therein an aperture, a, cylindrical lens rotatably mounted on said trunnions and extending through said aperture into said housing, said lens engaging one side of said film to guide the same and being adapted to direct light from said source to said film, and a projection lens in line with said light source and said cylindrical lens and said film.

2. In a projector including a movable film and a housing containing a light source, in combination, trunnions on said housing, said housing having formed therein an aperture, a cylindrical lens rotatably mounted on said trunnions and extending through said aperture in said housing, said lens engaging one side of said film to guide the same and being adapted to direct light from said source to said film, a projection lens in line with said light source and said cylindrical lens and said film, and a bail swingable on said trunnions to disengage said film from said cylindrical lens.

3. In a projector, a light source, an objective lens, a rotatable cylindrical condensing lens positioned to receive light from said source and to deliver light to said projection lens, a film magazine having aligned apertures therethrough one of which partially embraces said cylindrical lens when said magazine is normally positioned in said projector, a pair of reels in said magazine, a film on said reels spanning said last aperture and adapted to frictionally engage said cylindrical condensing lens when said magazine is normally positioned in said projector, and means for rotating at least one of said reels to move the film.

4. In a projector, a light source, an objective lens, a rotatable cylindrical condensing lens positioned to receive light from said source and to deliver light to said projection lens, a film magaxzine having aligned apertures therethrough one of which partially embraces said cylindrical lens when said magazine is normally positioned in said projector, a pair of reels in said magazine, a, film on said reels spanning said last aperture and adapted to frictionally engage said cylindrical condensing lens when said magazine is normally positioned in said projector, and means for rotating one of said reels to move said film in one direction and the other of said reels to move the film in the opposite direction.

5. In a projector, a lamp house having an aperture formed therein, a source of light in said lamp house, an objective lens, a rotatable cylindrical lens positioned between said source and said objective lens, said aperture partially embracing one side of said cylindrical lens, a film magazine having aligned apertures therethrough one of which partially embraces the other side of said cylindrical lens when said magazine is normally positioned in said projector, a pair of reels in said magazine, a film on said reels spanning said last aperture and adapted to frictionally engage said cylindrical condensing lens when said magazine is normally positioned in said projec tor, and means for rotating one of said reels to move the film in one direction and the other 0! said reels to move the film in the opposite direction.

6. In a projector, a lamp house having an aperture formed therein, a source of light in said lamp house, an objective lens, a rotatable cylindrical lens positioned between said source and said objective lens, said aperture partially embracing one side of said cylindrical lens, a film magazine having aligned apertures therethrough one of which partially embraces the other side of said cylindrical lens when said magazine is normally positioned in said projector, a pair of reels in said magazine, a film on said reels spanning said last aperture and adapted to irictionally engage said cylindrical lens when said magazine is normally positioned in said projector, means associated with said cylindrical condensing lens and concentrically movable thereabout for retracting said film from said cylindrical lens when said magazine is to be removed from the projector, and means for rotating one of said reels to move the film in one direction and the other of said reels to move the 1 film in the opposite direction. 1

7. A projector according to claim 6, wherein said retracting means comprises a bail extending over the length of said cylindrical lens and hav ing at one end thereof a shoe inclined toward the axial line of the cylindrical lens and adapted to engage and hold the portion of the film spanning said last aperture clear of said cylindrical lens while said film magazine is being positioned in the projector and adapted to be moved out of engagement with the film when the magazine is normally positioned in the projector, thereby guiding the film into circumferential registry with said cylindrical lens.

8. A projector according to claim 6, in which a shield is positioned in said lamp house and provided with an aperture smaller than said first aperture in said lamp house and adapted to define the size of a beam oilight passing through said cylindrical lens.

9. In a projection device, a cylindrical condensing lens, a light source spaced apart from said lens and outside the periphery thereof, a film magazine having aligned apertures therethrough, one of which partially embraces said cylindrical condensing lens, a pair of reels in said magazine, a film supported on said reels spanning said last aperture and engaging an arc of the circumference of said lens whereby light from said source may pass through said film and the body of said lens and emerge therefrom at a point circumierentially opposite to its point oi entry, and a projection lens spaced apart from said cylindrical lens and outside the periphery thereof and located in the emergent beam therefrom.

VERNEUR- E. PRATT. 

